The polyphenylene ether resins are a well-known family of linear thermoplastic engineering resins. A wide variety of these resins and a number of methods for their preparation are disclosed in Hay, U.S. Pat. Nos. 3,306,874 and 3,306,875, as well as in Stamatoff, U.S. Pat. Nos. 3,257,357 and 3,257,358.
It is a characteristic of the thermoplastic polyphenylene ether resins that they have a high viscosity in their molten state. This characteristic places a comparatively low limit on the rate at which the resins can be molded at safe temperatures in injection molding machines, and increases the power required to maintain a given rate of production from extrusion machines operating at a safe temperature. By "safe" is meant a temperature which does not cause depolymerization, oxidation or other degradation of the resin. Attempts have been made to employ organic compounds as viscosity depressants. For instance, it is known that triphenyl phosphates can be used as a processing aid to depress the melt viscosity of molten polyphenylene ether resins.